Running out of gas can be frustrating and sometimes even dangerous. The best way to prevent it from happening is to be prepared. Try to keep your gas tank at least half-full at all times. Why half full? Because gas gauges are notoriously inaccurate. That quarter of a tank reading you have may be closer to empty than you think, so why not play it safe? If your car's fuel injected, it's doubly important to avoid running out of fuel. When air gets into the fuel lines of an injected vehicle, it may be extremely difficult to start the car without damaging something, and often it takes a mechanic to solve the problem. Don't pump the gas pedal repeatedly when trying to start a car that's run out of fuel. One pump to set the automatic choke should be fine. If the car doesn't start after cranking the starter for fifteen seconds, wait a few minutes and then try it. Damage to the starter could result from excessive cranking. If your car's gauge reads that there's plenty of gas and it still won't start, there could be a problem with some other component of the fuel system. Contact a qualified mechanic if you suspect a problem with your car's fuel system.